The effect of free nitrous acid on the anabolic and catabolic processes of glycogen accumulating organisms

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Original languageEnglish
Pages (from-to)2901-2909
Journal / PublicationWater Research
Issue number9
Publication statusPublished - May 2010
Externally publishedYes


Nitrite/Free Nitrous Acid (FNA) has previously been shown to inhibit aerobic and anoxic phosphate uptake by polyphosphate accumulating organisms (PAOs). The inhibitory effect of FNA on the aerobic metabolism of Glycogen Accumulating Organisms (GAOs) is investigated. A culture highly enriched (92 ± 3%) in Candidatus Competibacter phosphatis (hereafter called Competibacter) was used. The experimental data strongly suggest that FNA likely directly inhibits the growth of Competibacter, with 50% inhibition occurring at 1.5 × 10-3 mgN-HNO2/L (equivalent to approximately 6.3 mgN-NO2-/L at pH 7.0). The inhibition is well described by an exponential function. The organisms ceased to grow at an FNA concentration of 7.1 × 10-3 mgN-HNO2/L. At this FNA level, glycogen production, another anabolic process performed by GAOs in parallel to growth, decreased by 40%, while the consumption of polyhydroxyalkanoates (PHAs), the intracellular carbon and energy sources for GAOs, decreased by approximately 50%. FNA likely inhibited either or both of the PHA oxidation and glycogen production processes, but to a much less extent in comparison to the inhibition on growth. The comparison of these results with those previously reported on PAOs suggest that FNA has much stronger inhibitory effects on the aerobic metabolism of PAOs than on GAOs, and may thus provide a competitive advantage to GAOs over PAOs in enhanced biological phosphorus removal (EBPR) systems. © 2010 Elsevier Ltd. All rights reserved.

Research Area(s)

  • Aerobic metabolism, Enhanced biological phosphorus removal, Free nitrous acid, Glycogen accumulating organisms, Inhibition, Nitrite

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